Undescribed Sawfly Gall on S. lucida Muhl.

This gall consists of an enlargement of either the petiole or midrib of S. lucida. Neither of these organs bears, as a rule, more than one gall at a time, but occasionally the petiole of a leaf carries two or even three and the midrib in rare instances two.

The midrib galls are fairly regularly elliptical in outline with the shorter diameter across the leaf. The swellings in most cases are nearly equally divided between the upper and the lower leaf surfaces. The petiole galls vary from spherical to ovoid in shape. In the latter case the smaller end of the gall is towards the apex of the leaf.

Dimensions of the gall: — Longer diameter 6-12 mm.; shorter diameter 3-7 mm.

The very marked proliferation of tissue in this gall is not accompanied by a differentiation that presents many points of interest. The cells are larger than those of the normal leaf and the nuclei are correspondingly larger. The bundle is cut nearly through by the ovipositor (Fig. 82). The free ends of the bundle thus stimulated grow out until in some cases they almost surround the gall. This elongation is produced in part by the increased diameter of the vessels but also by the production of new cellular elements.

The pith, exposed by the cutting of the bundle, produces almost all the abnormal tissue (Figs. 83, 84), but the cortex contributes some. The cells are arranged in curved lines that pass across from one elon- gated end of the bundle to the other. Between these rows are many air spaces which are elongated in the direction of the lines of cells (Fig. 84).

Pontania lucidae, new species

Toronto, Ontario. Males and females bred from galls on Salix lucida, by A Cosens.

Pontania lucidae

Salix
Leaf galls

Petiole or midrib enlargement, spherical to ovoid, dimensions .25 to .5 inch, on S lucida, sawfly, spring

Pontania lucidae

Host: Salix lucida

The gall is produced as an enlargement of the petiole or midrib of the leaf. Throughout the district in general this species is not common.

Range: Toronto, Ontario

Pontania lucidae

Type locality. — Toronto, Ontario, Cana- da.

Host plant. — Salix lucida (original identification confirmed by G. Argus).

Notes. — A valid species in Pontania (Eupontania), closely related to Pontania consors as was stated by Rohwer. The examined leaves of Salix lucidae bear only a few typical leaf galls associated with midribs. The rest of the galls in this sample might rather be called petiole or midrib galls (Fig. 8). We are not sure if all of these galls belong to the species described by Rohwer or if some of them are Euura galls.